Cytological Studies in the South Indian Acanthaceae. 1. Genus Barleria L.

Abstract

Cytology of eight species of Barleria from South India is reported. All the species have n=20 and 2n=40. Meiosis was fairly normal in all except one species (B. courtallica) in which IV, III, II and Is were consistently noticed. Somatic chromosomes were large sized, and the karyotypes were fairly symmetrical and unspecialised (2B) in all except B. acwninata (3B).All the known species are tetraploids based on x=10. Meiotic behaviour in all the present species except B. courtallica was suggestive of their alloploid nature, while B. courtallica auto-tetraploid.Cytological evidence is shown to support separation of Barleria (large sized chromosomes) from Bentham and Hooker's Justicieae as done by Lindau and Bremekamp. Further, the delinking of Barleria (x=10, large chromosomes and trinucleate pollen) and Lepidagathis, (x=11, small chromosomes, and binucleate pollen) from Lindau's same tribal fold and their placement in different tribes proposed by Bremekamp is pointed out to be appropriate.